C3 Overheating

[TimC]

My wife's C3 is overheating with the radiator fan never kicking in.

 

I've connected a Foxwell NT200 and there are no fault codes present.

 

Letting the engine idle and watching the engine temp rise - via the Foxwell - I see that when it reaches 90C the thermostat must be opening  as the temp then drops down. On further idling it slowly rises to 101C & beyond with no sign of the rad fan starting.

 

If I turn on the A/C the radiator fan immediately kicks in & the temp drops accordingly. This I believe is correct .

 

I know there are 2 sensors for the coolant system & obviously the one for the coolant temp is fine, not sure about the other one or exactly what triggers the rad fan.

 

The radiator is getting very hot so water is circulating to it OK.

 

Any guidance would be much appreciated.

Edited June 27, 2015 by TimC

[Randombloke]

There will be a second thermostat that turns the radiator fan on.

 

Normally it should click on when the temperature reaches a point specified in the Haynes manual or similar.

 

If you haven't got one then worth Googling for images or diagrams of your engine.

[paul.h]

Welcome to the forum.

 

I am guessing you have a 2002 to 2009 C3 with the 1.4 petrol engine.

 

If so there are 2 temperature sensors at the gearbox end of the cylinder head, one on the top and one on the side. The top one does the gauge and fan and the side one does a high temperature alarm at 118°C and the fan. The fan should start at 96°C on low speed and cut out when it drops to 94°C. If the temp continues to rise the fan will go to its high speed. The fan also runs if the air con is switched on. The thermostat should start to open at 89°C.

 

Is the gauge showing a high temp - on our 2003 C3 3 bars would be a range of about 80 to at least 96°C.

 

The Haynes manual wiring diagrams show with air conditioning the fan has a control unit as part of it and not a relay (as for fans without air con) with 2 supplies from the engine control unit. It also has a 12 volt battery supply from maxi fuse MF1 in the engine fusebox, an earth and a combined fused and relay supply from the engine fusebox fuse F8. I would check the wiring and connections on the fan for any damage/bad connections (Haynes shows 2 connectors at the top of the fan shroud) but if nothing is found you may possibly need a new fan control unit.

[TimC]

Yes it's a 1.4 8 valve petrol version. However, I can only find 1 sensor on the cylinder head at the gearbox end strangely which differs from what you (and others) say & the Haynes manual.

 

There is no temperature gauge on the display, it's a Desire version.

 

The engine fuse box layout is different from that in the handbook but I managed to get the correct layout from the Citroen service website.

 

At the moment I'm confused but am taking to an independent Citroen specialist tomorrow so we'll see.

Edited July 6, 2015 by TimC

[paul.h]

What year is your car ? For the 2002 to 2009 C3, the parts diagrams show one temp sensor on the thermostat housing. Also there is a second connector shown on the end of the cylinder head below the thermostat housing. For the 2009 on C3 which does not have a temp gauge, there is only one sensor shown and this is on the thermostat housing

 

It could be the fan not running is a problem with the relay or controller on the fan itself. It is possibly not the temp sensor since you are getting what appear to be good readings on your code reader.

 

You can see the parts diagrams as a free service on the service.citroen site if you register as another professional and a member of the Citroen Owners Club. Then use your VIN (VIS) top left to find your car. The housing temp sensor can be found under Mechanical, Engine, Cooling System, Outlet tank switch probe and the cylinder head sensor under Mechanical, Engine, Cylinder head, Cylinder head - cover..

[TimC]

Mine is a 2006 , which seems to have many similarities with the 2009 version.

 

Anyway turns out the fan controller mounted on the rad is faulty according to my local independent experts. New one ordered so we'll soon see.

[Muggle]

My wife has a 03 reg C3, with a 1.4i petrol engine - since this topic relates to a problem it has, may I use this to seek help with my problem?

 

The temp gauge shows normal most of the time (3 bars illuminated), until suddenly it will show maximum (all bars lit up) - this happens in a moment, not gradually. When all the bars are lit up the radiator fan switches on, but in a few seconds the temp gauge shows normal and the fan stops. The car runs normally and even on a long trip does not overheat at all and so I'm assuming that it is an indication fault rather than an overheating one.

 

I have replaced the temperature sensor (I can only see one - on top, to the right side of the engine), but this makes no difference. A friend connected a computer to it and read a fault code, which is P0485, cooling operation in ECU interrupted.

 

Does this mean anything to the members and can anyone suggest my next step in finding the cause of this weird behaviour??

 

KC

Edited October 31, 2016 by Muggle

[paul.h]

This is from the common problems topic and includes links to other topics about the same problem. On here P0485 gives definition P0485 Cooling Fan Power/Ground Circuit Malfunction, but you should check to see if the fault code comes back after it has been deleted.

 

30. High temperature warnings.

This topic by Skyman fixed the problem using a dealer supplied temp sensor after trying a low cost ebay one which did not work http://www.citroen-o...-by-new-sensor/

 

This occurred on our 2010 C3 1.4 VTI 96 bhp. A check on live data showed the engine coolant temperature was normal yet the high temperature warning was lit and the engine fan was running continually. A visit to the Citroen dealer for a new temperature sensor however brought up that Citroen had just issued a recall for faulty temperature sensors on the EP engines so it would be fixed without cost to ourselves. This is done by replacing the temperature sensor with a new one or as in our case where the temperature sensor is not removeable from the thermostat housing, the housing bleed screw is removed and the temperature sensor is put in its place along with a short wiring loom.